|
Ketamine is a general dissociative anesthetic for human and veterinary use. Its hydrochloride salt is sold as Ketanest®, Ketaset® and Ketalar®. Pharmacologically it is very similar to Dextromethorphan and phencyclidine (PCP).
Ketamine was first used on American soldiers during the Vietnam War, but is often avoided now because it can cause unpleasant out-of-body experiences. It is still used in human medicine as a first-choice anesthetic for victims with unknown medical history (e.g. from traffic accidents), in podiatry and other minor surgery, and occasionally for the treatment of migraine.
In veterinary medicine, ketamine is often used for its anaesthetic and analgesic affects on cats, dogs, rabbits, rats, and other small animals. Veterinarians often use ketamine with sedative drugs to produce balanced anaesthesia and analgesia and also use ketamine as a constant rate infusion to help prevent pain wind-up. Ketamine is often used with horses and other large animals, but it has less effect on bovines.
Ketamine may be used in small doses (0.1 - 0.5 mg/kg/hr) as an analgesic, particularly for the treatment of pain associated with movement and neuropathic pain. It has the added benefit of counter-acting spinal sensitization or wind-up phenomena experienced with chronic pain. At these doses, the psychotropic side effects are less apparent and well managed with benzodiazepines. It is a co-analgesic, requiring concomitant low-dose opioid to be effective.
Ketamine effects as a depressesent on the respiratory and circulatory are less than other anesthetics. When used in anesthetic doses, it sometimes stimulates the circulatory system rather than depresses it. It is sometimes possible to perform ketamine anesthesia without protective measures to the airways. Ketamine is also a potent analgesic and can be used in sub-anesthetic doses to relieve acute pain; however, its psychotropic properties must be taken into account.
There is research going on in its usefulness in pain therapy and for the treatment of alcoholism and heroin addiction.
Ketamine is a Schedule III drug in the United States, and is used in many other countries, such as Mexico. Patients sometimes reported going into other worlds or seeing God while anesthetized. These unwanted psychological side-effects made ketamine less used.
Psychopharmacologically it is a non-competitive glutamate inhibitor at the NMDA receptors. These occur mainly in the hippocampal formation and in the prefrontal cortex, which explains ketamine's profound effects on memory and thought.
History
Ketamine was first synthesized in 1962, as an attempt to find a safer alternative to PCP. The first psychedelic use of Ketamine was in 1965. Ketamine would increase in popularity in 1978, thanks to the publication of several books, including "The Scientist" by John Lilly, which documented his ketamine, LSD, and isolation tank experiments. Ketamine was placed in Schedule III of the United States Controlled Substance Act in August 1999.
Recreational Use
When used recreationally, it is known as K, Ket, Special K, Vitamin K (not to be confused with the true Vitamin K) and Kitty.
Ketamine produces effects similar to PCP, and DXM. Like other dissociative anesthetics in low- to upper-middle dosages, its hallucinogenic effects are only seen against a background lacking sensory stimulation, such as darkness. Users tout its trip as better than that of PCP or LSD because its overt hallucinatory effects are short-acting, lasting an hour or less, in most cases. Effects on the senses, judgment, and coordination, however, can last for 18 to 24 hours. Ketamine sold on the streets comes from diverted legitimate supplies, primarily veterinary clinics, in either powdered or liquid form. In powdered form its appearance is similar to that of pharmaceutical grade cocaine and can be insufflated (snorted, also known as "taking bumps"), placed in beverages, or smoked in combination with marijuana. Oral use usually requires more material, but has a longer duration. The liquid can be heated to drive off the solvent (usually saline), leaving powder, or it can be injected.
In therapeutic and psychedelic use, the liquid is injected intra-muscularly, though for all intents and purposes, intravenous self-injection is impossible, as well as dangerous, as the user would be so quickly numbed as to be unable to finish the injection. The incidence of recreational ketamine use is increasing, and accounts of recreational ketamine use appear in reports of rave parties attended by teenagers and young adults. This lead to the scheduling of the drug in 1999.
Like the other dissociative anesthics DXM and PCP, hallucinations caused by ketamine are fundamentally different than those caused by tryptamines and phenethylamines. While at low doses the user must be in a dark room or have his eyes closed in order to see any hallucinations, at medium to high doses the effects are far more intense and obvious and include changes in the perception of distances and durations, and the visual system being slow to update what the user is seeing. There are reports of high dosage users who tell about being able to see their surroundings in two sharp images, as if the brain is unable to merge the images each eye is sending.
Ketamine puts the user in a dissociated state, meaning that they are not connected to a sense of self, or to reality around them. If a large enough amount is taken, the user may go through a "K-hole" and experience other worlds or dimensions that are impossible to describe in our language, while being completely unaware of their individual identity or the outside world. A user may feel as though her perception is located so deep inside his/her mind that the real world seems distant (hence the use of a "hole" to describe the experience). Often users do not remember this part of the experience after regaining consciousness. The "re-integration" process is slow, and the user gradually becomes aware of things around them. At first they may not remember their own name, or even know that they are human, or what that means. Movement is extremely difficult, and users may not be aware that they have a body at all. It may be possible to use this state therapeutically, taking advantage of the dissociation and removing associations from the user's brain. After the experience is over, some of these changes may remain.
Some drug users' first contact with ketamine is accidental, often from a pill sold as something else (commonly Ecstasy). Ketamine is also commonly combined with other drugs to enhance their effects.
See also
External links
|
